The Russian Mennonites (German: "Russlandmennoniten" occasionally Ukrainian Mennonites) are a group of Mennonites of German language, tradition and ethnicity, who are descendants of German-Dutch Anabaptists who settled for about 250 years in West Prussia and established colonies in the south west of the Russian Empire (present-day Ukraine) beginning in 1789. Since the late 19th century, many of them have come to countries throughout the Western Hemisphere. The rest were forcibly relocated, so that few of their descendants now live at the location of the original colonies. Russian Mennonites are traditionally multilingual with Plautdietsch (Mennonite Low German) as their first language and lingua franca. The term "Russian Mennonite" refers to the country where they resided after the split from Germany and not to their ethnic heritage. In 2014 there are several hundred thousand Russian Mennonites: about 200,000 in Germany, 100,000 in Mexico, 70,000 in Bolivia, 40,000 in Paraguay, 10,000 in Belize and tens of thousands in Canada and the US and a few thousand in Argentina, Uruguay and Brazil.
In the early-to-mid 16th century, Mennonites began to move from the Low Countries (especially Friesland) and Flanders to the Vistula delta region, seeking religious freedom and exemption from military service. They gradually replaced their Dutch and Frisian languages with the Plautdietsch dialect spoken in the area, blending into it elements of their native tongues. Today Plautdietsch is the distinct Mennonite language which developed over a period of 300 years in the Vistula delta region and south Russia. The Mennonites of Dutch origin were joined by Mennonites from other parts of Germany including the German speaking parts of what is today Switzerland. Some few Poles became Mennonites and were assimilated into the Vistula delta Mennonites.